Method for splitting oriented plastic materials into fibrous structures

ABSTRACT

This is a method and apparatus for splitting oriented plastic sheet materials such as films, ribbons, etc. into fibrous structures. The material to be split is moved in a first direction. The direction in which the material is moving is changed so that the second direction makes an acute angle with the first direction. Simultaneously with the change in direction or movement of the material a plurality of disruptive forces are applied to the material substantially in the direction of the movement of the material to split the oriented material into a fibrous structure.

United States Patent Kalwaites [is] 3,656,672 51 Apr. 18,1972

[54] METHOD FOR SPLITTING PLASTIC MATERIALS INTO FIBROUS STRUCTURES [72]Inventor: Frank Kalwlltes, Somerville, NJ. 731 Assignee: 1M & JOIIMII[22] Filed: Aug. 11, 19 69 [2]] Appl. No.: 870,876

Related US. Application Data [62 Division of Ser. No. 710.532, Mar. 5,I968, Pat.

No. 3,520,458 A I v [52] U.S. Cl. ..225/3, 28/DlG. l [5 l 1 Int. Cl.132613/02 [58] FieldofSearch .'.....28/l F; 225/93,9 7, 3,98;

[56] Reierences Cited UNITED STATES PATENTS 3,416,714 12/1968 Skinner..225/93 3,470,285 9/1969 Kim. a ..22s/3x 3,474,611 10/1969Suzukietal..... .....22s/3x 3,427,912 '2/1969 Nozawaetal ..83/678XPrimary Examiner-James M. Meister I Attomey-Robert L. Minier, John H.Tregoning and Alexander T. Kardos ABSTRACT This is a method andapparatus for splitting oriented plastic sheet materials such as films,ribbons, etc. into fibrous structures. The material to be split is movedin a first direction. The

direction in which the material is moving is changed so that the seconddirection makes an acute angle with the first direction. Simultaneouslywith the change in direction or movement of the material a plurality ofdisruptive forces are applied to the material. substantially in thedirection of the movement of 'the material to split the orientedmaterial into a fibrous structure.

i -5 Claims, 3 Drawing Figures METHOD FOR SPLITTING ORIENTED PLASTICMATERIALS I O ROU This is a division of application ser; No. 710,532,filed March 5, 1968, Pat. No. 3,520,458. v

This invention relates to a method for splitting oriented plasticmaterials to form fibrous materials. Materials which may be treated inaccordance with the present invention are sheet materials such as films,narrow tapes, etc. All of the starting materials are highly oriented inone direction (i.e., unilaterally oriented) to a sufficient degree sothat forces will disrupt the material and split it into a fiber network.This is generally termed a fiberproducing orientation and is a highdegree of parallel orientation in one direction with very littlestrength to the film in the direction perpendicular to the direction oforientation.

It, has been known for some time that fibrous sheets or split fiber websmay be produced by orienting plastic materials to a fiber producingorientation and then applying forces to disrupt the material and splitit into a fibrous network. I have developed an improved method andapparatus for uniformly and completely splitting oriented plasticmaterial into fibrous networks. My apparatus is very simple and may beoperated at virtually any speed.

in accordance with the present invention plastic sheet material which isoriented to a fiber producing orientation is moved in a first direction.The direction in which the sheet material is moving is changed to asecond direction making an applied to the material to split the orientedplastic material into a fibrous network.

The apparatus for carrying the method of the present invention intopractice comprises a rotatable roll having a stationary blade intangential contact with the surface of the roll along a line parallel tothe axis of the roll. The oriented plastic material passes between theroll and the blade and about the edge of the blade. Immediately adjacentthe edge of the blade and rotating in the same direction as the firstroll is a rotating brush roll so that the material moves about the edgeof the blade and simultaneously the brush roll places disruptive forcessubstantially in the longitudinal direction of the material as thematerial passes about the blade. Preferably the rotatable brush rollrotates at a faster peripheral linear speed than the speed of thematerial being treated.

The invention will be more fully described in conjunction with theaccompanying drawings wherein:

carrying out the method of the present invention;

FIG. 2 is a top view of the splitting mechanism for carrying.

out the method of the present invention;

FIG. 3 is an enlarged cross-sectional view of the splitting mechanism ofFIG. 2.

Referring to FIG. 1 a roll of plastic film which has been oriented to afiber producing orientation is mounted for rotation in suitable framing11. The plastic material may be any of the standard orientable plasticmaterials such as the polyolefins; that is, polyethylene andpolypropylene. Other plastic materials such as polyamides or polyestesmay be used. The important thing is that the plastic material beoriented in one direction to an extent that it readily forms fibers asis well known in the art.

The plastic material is then passed through a pair of guide I rolls l2and 13 mounted for rotation in suitable framing 14. These rolls may bedriven or may merely idle if subsequent rolls are driven. lf rolls aredriven it is preferred they have a roughened surface to provide a bettergrip and more uniform feed of the material.

The plastic material passes between the nip fonned by a rotatable roll15 mounted for rotation in suitable framing 21 and a stationary blade 16also mounted in the framing 21 with the stationary blade in tangentialcontact with the rotatable roll. This rotatable roll may have a slightlyroughened surface such as a sandblasted, knurled, or even a fluted orgrooved surface. The roll may be made from any of the relatively hardmetals or even a very hard rubber. The blade is preferably a temperedsteel blade which has resilience to allow the material to pass betweenthe blade and the roll. Preferably the blade extends slightly past thetangent line of contact with the roll though it may tenninate exactly atthe contact line. The edge of the blade is preferably rounded so as notto rip or tear the material.

set of guide rolls 18 and 19 mounted for rotation in the framing 21 andis wound up on standard wind-up mechanisms 20.

Referring to FIGS. 2 and 3 the oriented plastic material 25 from theguide roll 26 passes about a portion of the surface of the rotatableroll 27 and between this roll and the stationary blade 28 which is intangential contact with the surface of the roll and extends slightlypast the point of tangential contact.

' Theguide roll is mounted for rotation in bearings 29 mounted insuitable framing 30 and is driven by means of a suitable motorand pulley31. The rotatable roll is also mounted for rotation in bearings 32mounted in suitable framing 33 and is driven by standard means 34. Theplastic material after passing about the blade is then carried away by asecond pair of guide rolls 35 mounted for rotation in bearings 36mounted in the frame 33. These rolls may also be driven by standardmeans 37. The rotatable roll rotates in the direction 'of the arrow asshown in FIG. 3 so that it is moving in the same direction .as theplastic material is moving. Positioned immediately adjacent the nipblade is a rotatable brushing roll 40. The brush roll is mounted forrotation in bearings 41 applies the forces to the plastic material tosplit it be sufficiently resilient so as-not to tear the film but nottoo resilient so that they have no action on the film. It has been foundthat the bristles should have a length of at least one-fourth inch andpreferably three-eights inch and a diameter of at least 0.014 inch. Thebristles should be made of a relatively stiff material such as metalwires. Soft nylon bristles or similar softer bristles will not work inaccordance with the present invention. The number of bristles may varyfrom about l00 per square inch to 200 per square inch or even higher asdesired.

The oriented plastic material on being passed about the edge of the nipblade to change its direction at an acute angle and being simultaneouslybrushed to have disruptive forces placed over the material is brokeninto a network of split fibers.

Although all of the various holders, pulleys, belts, or like mechanicalmeans including some framing have not been illustrated completely in thedrawings or described in the specification it is to be appreciated thatsuch elements have been omitted to keep the drawings and descriptionsdistinct and to avoid introduction of matters which are well knownexpedients in the art. The mechanical driving means and various frameswhich are used are conventional and merely involve the application ofwell known principles.

The invention will be further illustrated in greater detail by thefollowing specific examples:

EXAMPLE I A polyethylene film 2 mils in thickness and about 15 incheswide, highly oriented in the longitudinal direction of the film ispassed through the apparatus depicted in FIG. 3. The input roll is ametal roll with a knurled surface in a diamond pattern. The brush rollhas wire bristles having 0.018 inch diameter,

the entire surface of thematerial substantially at the same time thatthe material is bent at an acute angle to itself to produce the greatlyimproved, uniform splitting of the oriented plastic material.

Although several specific examples of the inventive concept have beendescribed for purposes of illustration the invention split fiber web ofinterconnected fibrous elements. The

splitting is uniform throughout the entire area of the film.

EXAMPLE [I FIG. 3. The input roll is a metal roll with a sandblastedsurface. The brush roll has bristles 0.014 inch in diameter which arewireand are three-eights inch long and has approximately I80 bristlesper square inch. The roll and the brush roll rotate in the direction asshown by the arrows in FIG. 3 and the brush roll rotates at four timesthe speed of the metal roll. A spring steel blade having a thickness of0.020 inch and rounded at its outer edge is placed in contact with thesurface of the input roll. The film is passed through the blade and pairof rolls at a speed of 9 feet per minute and the oriented film is splitinto a split fiber web of interconnected fibrous elements. The splittingis uniform throughout the entire area of the film.

Though the apparatus and method have been more fully described withregard to operation on a plastic material which is oriented in the longdirection it will work equally well as shown by the examples on plasticmaterials oriented in the cross direction. The important thing is toapply the disruptive force which is quite randomly applied by thebrush-roll over should not be construed as limited thereby nor tothespecific features mentionedtherein exceptas the same maybe included inthe claims as appended hereto. It is understood that changes,modifications, and variations maybe made in the method and apparatusherein described without departing from the spirit and scope of theclaimed invention.

I claim:

l. A method of continually treating oriented plastic material to producea split fiber'web comprising: continually moving the material to betreated in a first direction, changing the direction at an acute angle.to said first direction by passing said material over the edge of ablade while substantially simultaneously applying disrupture forces tothe material whereby the material is uniformly split into a fibernetwork.

2. Method accordingto claim 1 wherein-the disrupted forces are appliedsubstantially only in the longitudinal direction of the material.

3. Method according to claim 1 wherein the disrupted forces are appliedrandomly across the entire width of the material.

4. Method according to claim 1 wherein the oriented plastic material isoriented in its longitudinal direction.

5. Method according to claim 1 wherein the oriented plastic material isoriented in its transverse direction.

1. A method of continually treating oriented plastic material to producea split fiber web comprising: continually moving the material to betreated in a first direction, changing the direction at an acute angleto said first direction by passing said material over the edge of ablade while substantially simultaneously applying disrupture forces tothe material whereby the material is uniformly split into a fibernetwork.
 2. Method according to claim 1 wherein the disrupted forces areapplied substantially only in the longitudinal direction of thematerial.
 3. Method according to claim 1 wherein the disrupted forcesare applied randomly across the entire width of the material.
 4. Methodaccording to claim 1 wherein the oriented plastic material is orientedin its longitudinal direction.
 5. Method according to claim 1 whereinthe oriented plastic material is oriented in its transverse direction.